Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
vector<int> cl(vector<int> A) {
  for (int i = 0; i < A.size(); i++) {
    A[i] = 0;
  }
  return A;
}
int qweq(int x) {
  long long cc = 0;
  while (x > 0) {
    cc += x % 10;
    x /= 10;
  }
  return (cc);
}
int main() {
  long long q = 999999999, n, w, e, r = 0, k, ww, m, qq = 0;
  string ans = "";
  cin >> n >> m;
  vector<vector<int>> v(n);
  vector<vector<int>> kek(n);
  vector<vector<int>> lol(n);
  for (int i = 0; i < n; i++) {
    for (int ii = 0; ii < m; ii++) {
      cin >> w;
      v[i].push_back(w);
      kek[i].push_back(w);
      lol[i].push_back(w);
    }
  }
  for (int i = 0; i < n; i++) {
    for (int ii = 0; ii < m; ii++) {
      q = min(q, (long long)lol[i][ii]);
    }
    for (int ii = 0; ii < m; ii++) {
      lol[i][ii] -= q;
    }
    qq += q;
    q = 999999999;
  }
  q = 999999999;
  for (int i = 0; i < m; i++) {
    for (int ii = 0; ii < n; ii++) {
      q = min(q, (long long)lol[ii][i]);
    }
    for (int ii = 0; ii < n; ii++) {
      lol[ii][i] -= q;
    }
    qq += q;
    q = 999999999;
  }
  for (int i = 0; i < m; i++) {
    for (int ii = 0; ii < n; ii++) {
      q = min(q, (long long)kek[ii][i]);
    }
    for (int ii = 0; ii < n; ii++) {
      kek[ii][i] -= q;
    }
    r += q;
    q = 999999999;
  }
  q = 99999999999;
  for (int i = 0; i < n; i++) {
    for (int ii = 0; ii < m; ii++) {
      q = min(q, (long long)kek[i][ii]);
    }
    for (int ii = 0; ii < m; ii++) {
      kek[i][ii] -= q;
    }
    r += q;
    q = 999999999;
  }
  if (r > qq) {
    for (int i = 0; i < n; i++) {
      for (int ii = 0; ii < m; ii++) {
        q = min(q, (long long)v[i][ii]);
      }
      for (int ii = 0; ii < m; ii++) {
        v[i][ii] -= q;
      }
      for (int j = 0; j < q; j++) {
        ans += "row ";
        ans += to_string(i + 1);
        ans += "\n";
      }
      q = 999999999;
    }
    q = 999999999;
    for (int i = 0; i < m; i++) {
      for (int ii = 0; ii < n; ii++) {
        q = min(q, (long long)v[ii][i]);
      }
      for (int ii = 0; ii < n; ii++) {
        v[ii][i] -= q;
      }
      for (int j = 0; j < q; j++) {
        ans += "col ";
        ans += to_string(i + 1);
        ans += "\n";
      }
      q = 999999999;
    }
  } else {
    for (int i = 0; i < m; i++) {
      for (int ii = 0; ii < n; ii++) {
        q = min(q, (long long)v[ii][i]);
      }
      for (int ii = 0; ii < n; ii++) {
        v[ii][i] -= q;
      }
      for (int j = 0; j < q; j++) {
        ans += "col ";
        ans += to_string(i + 1);
        ans += "\n";
      }
      q = 999999999;
    }
    q = 999999999;
    for (int i = 0; i < n; i++) {
      for (int ii = 0; ii < m; ii++) {
        q = min(q, (long long)v[i][ii]);
      }
      for (int ii = 0; ii < m; ii++) {
        v[i][ii] -= q;
      }
      for (int j = 0; j < q; j++) {
        ans += "row ";
        ans += to_string(i + 1);
        ans += "\n";
      }
      q = 999999999;
    }
  }
  long long cc = 0;
  for (int i = 0; i < n; i++) {
    for (int ii = 0; ii < m; ii++) {
      cc += v[i][ii];
    }
  }
  if (cc == 0) {
    cout << min(r, qq) << '\n';
    cout << ans;
  } else
    cout << -1;
  q = 99999999;
}